Forks or shocks possibly going bad

[willywill4765]

I'm getting a rear tire bad wear pattern I have realigned it twice had somebody check it said it was perfect and just the other day got done with a 65 mile charity ride and it looked even worse. Can anybody tell me if there's an easy way to tell if the fork fluid or the under the frame shocks are going bad what's an easy way to find out.

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[Sven]

I'd do some kind of meguyveer and veer over to the bathroom scale; extend a rear shock; maybe a 2x4 across the scale rather than an indent by the one end of the shock. As you press down to collapse it, match the same pressure with the other shock. Or the obvious would be; extending the rear shock rod out, and then hand push the two ends. One rod will make a fast collapse and then show resistance. Something like that might cause a weird pattern, but I kind of doubt it... don't hold me to it. Obviously if both are equal on the push - Not it.

While the shocks are off and wheel out, bike has to be centered upright as you lower the rear swing on a towel; laid on the garage floor say. The point is, who in the U-tips is touching first? Meaning, we have a bent swing that is not square? Both touch even - Not it.

Before you do all that, you'll have to move the belt off the sprocket and zip-tie it away from the wheel. Remove the brake caliper off and out of the way; as are [all] the spacers. Wheel goes back on with axle in place, and we first spin the wheel; looking at both rim sides for a bent rim bead. Next is the spin is still happening as you looked at the rear so it runs true, not the tire. If you want to see run-out and how bad, duct tape a flat screwdriver tip so you don't [want to] ding the rim moving it that close. Finding a resting spot for the handle end, that's horizontal at the bead, or most outer part of the rim. Too bad you can't do it with the tire on, but if X is the bead side, Y is the very edge of the rim as it spins that way.

Last is to still have the wheel in the swing with zero drag on the bearings. Simply find the tire valve and place it at 12 o'clock and move your hand away. Move the valve at 3-6-9 o'clock positions. The wheel should move - wheel is balanced [Not it]. For a little kicker on the 'come on, move you son-of-a'; is to palm the axle shaft [if you can] with both palms on the spin back and forth. You accomplish two things; one is to see that the axle spins true, and the little spin, bumps the wheel to fall either way, and/or comes up the other way.

Are we saying there is one side of the tire grooves gone on the one side and the other side has deeper rain grooves?
Are we checking the tire pressure before a ride? What's in it now? Might read it on the side of the tire, but that's max pressure with gear/passenger/etc. No reason why you can't run max all the time. Low pressure acts like a wide U pattern and turns slow. Pumped up, the tire kind of takes a V shape and turns like a hockey skate.

 

[Mickmorris]

Nice ride. What size rear tire on that Dog?

 

[Mickmorris]

I'd do some kind of meguyveer and veer over to the bathroom scale; extend a rear shock; maybe a 2x4 across the scale rather than an indent by the one end of the shock. As you press down to collapse it, match the same pressure with the other shock. Or the obvious would be; extending the rear shock rod out, and then hand push the two ends. One rod will make a fast collapse and then show resistance. Something like that might cause a weird pattern, but I kind of doubt it... don't hold me to it. Obviously if both are equal on the push - Not it.

While the shocks are off and wheel out, bike has to be centered upright as you lower the rear swing on a towel; laid on the garage floor say. The point is, who in the U-tips is touching first? Meaning, we have a bent swing that is not square? Both touch even - Not it.

Before you do all that, you'll have to move the belt off the sprocket and zip-tie it away from the wheel. Remove the brake caliper off and out of the way; as are [all] the spacers. Wheel goes back on with axle in place, and we first spin the wheel; looking at both rim sides for a bent rim bead. Next is the spin is still happening as you looked at the rear so it runs true, not the tire. If you want to see run-out and how bad, duct tape a flat screwdriver tip so you don't [want to] ding the rim moving it that close. Finding a resting spot for the handle end, that's horizontal at the bead, or most outer part of the rim. Too bad you can't do it with the tire on, but if X is the bead side, Y is the very edge of the rim as it spins that way.

Last is to still have the wheel in the swing with zero drag on the bearings. Simply find the tire valve and place it at 12 o'clock and move your hand away. Move the valve at 3-6-9 o'clock positions. The wheel should move - wheel is balanced [Not it]. For a little kicker on the 'come on, move you son-of-a'; is to palm the axle shaft [if you can] with both palms on the spin back and forth. You accomplish two things; one is to see that the axle spins true, and the little spin, bumps the wheel to fall either way, and/or comes up the other way.

Are we saying there is one side of the tire grooves gone on the one side and the other side has deeper rain grooves?
Are we checking the tire pressure before a ride? What's in it now? Might read it on the side of the tire, but that's max pressure with gear/passenger/etc. No reason why you can't run max all the time. Low pressure acts like a wide U pattern and turns slow. Pumped up, the tire kind of takes a V shape and turns like a hockey skate.

Damn it man! Sven, that’s a great reply. Hope you don’t mind I save that for future reference. I think you covered every possibility.

 

[willywill4765]

It's an Avon 300 on a 2007 big dog bulldog

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[Sven]

Thanks, Mick, but I think I missed a few.

With a ride to the hardware store, or welding supply house, buy a single welding rod or thin round-bar stock. Snip to size, meaning, one rod will have a bent L and that rests on the floor. The cut rod is going to slide next to the upright stationary rod with say tiny zip-ties. Bike has to be upright and squared, or sling a crank tie-strap over the garage rafters, hook the handlebars so the bike is about to be lifted; a level at the garage floor to check [not that it matters], then level the bike with a bubble leveler.

Go under one lower frame tube, raise the cut rod and let it touch the frame at the bottom. Swing the L so the sweep does not tag the frame, but more, pull one of the old lady's you know, place it between the rod and frame. Sweep the L and carefully remove it without moving the adjust rod. Go to the other side of the frame tube directly opposite of your choice of the first measurement. How many hairs off is it?

Might want to check 3 points alone the length of the lower frame. By holding the L with the thumb at the bottom, you can roll the rod in a sweep kind of pass. It hits - Maybe this might/not combo up and cause the shallow rain groove on the one side is the guess. Willy has to describe the wear pattern or send a photo from his 3 XL Pixel, because without a pattern, I'm just picking my nose.

Way out in left field, but square is square or triangulated is the front end setup. With the front wheel out of the way, the square is to again, palm the front axle and spin thru both forks. If say one is a screw in side, other side is just a round hole, palm the same way.

One fork remains static in the upper and lower crowns. You then float the other fork so the spin is effortless between the palms. Tighten the fork pinch bolts to spec; recheck palm spin. That front end is square to the triple-tree. The off-square is watching someone fight that axle going into the other fork. You can't push that axle in by hand, recheck your work. So, with a pea between you and the seat, one turn feels fine. Turn the other way it does not feel right. Strange, isn't it?

While each fork is on it's own spring pressure, grab the bath scale and push the fork up some. Go to the other fork and see if both feel equal or see pounds pressed as in; it goes something like this. Say the one spring is not as strong. The pressure of the frame on each spring sort of equals out, so it can't be the front end with perfectly squared forks when axle is inserted. Say for example the one spring rate is 10, and the sag spring is 9. Add/Divide = 9.5 is the average so it's not the front end setup/spring sag combo.

Willy has to show the front tire wear and does this too show a shallow rain groove on one side, a deeper groove on the other. Or is it 'stepped' at the center?

 

[Unsprung]

I'm getting a rear tire bad wear pattern I have realigned it twice had somebody check it said it was perfect and just the other day got done with a 65 mile charity ride and it looked even worse. Can anybody tell me if there's an easy way to tell if the fork fluid or the under the frame shocks are going bad what's an easy way to find out.

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Once tires start to wear, the wear pattern continues even with alignment corrections. I say that to say that your suspension components could be fine but the tire will continue to wear along it’s current track until replaced.

 

[willywill4765]

Well I guess in a way that's good news I hope you're right going to order me a new tire just not sure if I want to stay with Avon, I may try shinko's. This Avon always has about 4,000 mi on it

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[Mickmorris]

I was figuring your bike had the 300. Seems like I have read so many posts on how quickly they wear. I am going to guess mostly on the center . A pic would definitely help. 4000 miles is pretty good I would say, again based on other riders posts. I have a 180 on my BigDog & it wears even across the entire surface. I expect to get way more than 4000 miles out of it.

 

[bdm7250]

I have 5600 miles on my Shinko's and they still look new, I run 32psi in the rear which gives better contact patch and better wear in my opinion.

 

[willywill4765]

Here's two pics The first picture was taken today The other picture was taken August 11th of this year probably about 800 miles between pics. And like I said I had it realigned twice and it still getting worse.

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[willywill4765]

I guess I should have posted these pictures when I posted the message, first picture was taken today and the second picture was taken August 11th, probably about 800 to 1,000 miles between tire pictures

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[willywill4765]

Good looking paint job and the tires look awesome, wish mine look like that

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[bdm7250]

Left side wear is typically due to road crown, your contact patch on excessively crowned roads will be left of center of the tire. Your tire wear is not related to misalignment.

 

[Mikeinjersey]

I'm getting a rear tire bad wear pattern I have realigned it twice had somebody check it said it was perfect and just the other day got done with a 65 mile charity ride and it looked even worse. Can anybody tell me if there's an easy way to tell if the fork fluid or the under the frame shocks are going bad what's an easy way to find out.

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From your pictures it's obvious you will be getting a new tire. Before you go, check to see how your drive belt is tracking. If it tracks straight your adjustment is probably OK and it's likely BDM7250 is on the money. When the tire is off have the shop check your rear axle and you pivot axle for any sighs of wear. This video from Marky-Marc is excellent on the subject.

 

[Jwooky]

I typically get 8-10k miles out of mine. Been using Shinkos but have had Avon too.

Tire pressure is very important. They call for a very high 40psi which is not intuitive.
The Avon rep said for ever 1psi below 40, the temp will rise by 10 degrees due to side wall flex.

So at 30psi, the tire will run 100 degrees hotter which will accelerate breakdown and wear.

 

[Sven]

Wet the tire and walk it on a dry surface with bike upright. Once it dries as you roll, have someone stop you and there is your wear line. Is it [dry line] in the center?

Ride/drive to a few bike shops. Go to where they throwaway their used tires. If we have crowned roads, then these tires too will show the same pattern. There is your answer.

Biggest part of biking is not to be caught in a squid trap. You know, guy wears out a pair of shoes and only replaces the one = Squid!
You know any squids that just change the one worn tire and the front is what? Less miles, right? Handles how? STEPPED right in it we change single only.

Signed,
NOLTT (no one likes their tires)

 

[Sven]

Watched Marky's vid and thought this:

With another [aluminum] welding rod, it's easier to bend a U at the one end; that U or J hook is going to wrap around the lower swingarm tube. Same zipped slider rod is going to touch right under the top of the [inside] rim. Find the same lower point on the other side and did the rod:
a. Show the same distance under the rim.
b. Is the rod tip away from under the rim.
c. Did the tip stop at the very top [side] of the rim and can't go under.

Just don't know if the national traffic hwy system uses a generic all state road curve for rain drain, or their [county] engineers use something else in that state... only that bike shop with a stack of used tires knows for sure.

 

[Jersey Big Mike]

Here's two pics The first picture was taken today The other picture was taken August 11th of this year probably about 800 miles between pics. And like I said I had it realigned twice and it still getting worse.

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ok, first -- how many miles on that tire.
Once you see that pattern, you can not correct the continued wear on that tire.
Many K-9 riders see this loopsided wear on their 300's As long as my mileage is shorter than norm I stopped worrying about it personally.
I think the ONE tire that didn't do this I got 15K out of instead of my normal 10K, but no idea what was different before and after that tire.

 

[Minuteman]

There are a lot of factors to what has happened here. 1-everyone here is correct about once a tire starts to wear funny, you have no chance of saving it. 2-have you been replacing your wheel bearings each time you replace your tires., as the bearings may look good but have created there own wear with the tire that they were changed with before. 3-not sure where you live but road crown is a problem as we in the north see this all the time. 4-were there dyno beads put in with the new tire, as this helps with being balanced for more even wear. 5-it is possible that a bead had slipped on this tire causing excessive wear on 1 side, have had that happen before to me. 6-and last as BDM7250 mentioned running the tire with less pressure does work as I run my rear tire at 33-34 lbs when new for about 4-5000 miles as you have more road coverage on the tire wear a little more on the outside and then increase the pressure to 38-39 lbs which will allow me to get another 3-4000 miles added on, this may not work for every one, but my current tire has around 7500 miles and if it was not for the snow coming now I believe I could easily get another 1000 + miles. But will be changing this winter because I do not want to deal with it during the riding season. Just my 2-cents worth.